I would recommend checking this page that talks about system requirements on the Salesforce side:
Specifically it mentions these limits:
"In order for Tableau to connect to Salesforce data, all of the following must be enabled on both your company's account and your user profile:
- SOAP API for signing in
- REST API for getting meta data
- BULK API for downloading objects
- REST API for downloading objects that the BULK API does not support
- Replication SOAP APIs for retrieving changes in the data
To optimize for performance and ensure the APIs are available for all of their customers, Salesforce.com balances the load by limiting the number of concurrent API requests as well as limiting the total number of API requests overall. An error occurs if these limits are reached while connected using Tableau. See the Salesforce.com developer documentation to learn more about these limits.
Note: Some editions of Salesforce may not allow API access at all. Contact your Salesforce administrator to verify that your account has access to the above list of APIs.